The problems of emitting to the atmosphere industrial gases containing a high proportion of noxious substances have long been recognized. Acid gases such as the sulfur oxides, nitrogen oxides and the hydrogen halides are particularly common and undesirable components of industrial effluent gases. Bled to the atmosphere, such gases condense on water droplets forming strong acids and, blown about by wind, such droplets cause severe corrosion of metal parts and machinery even many miles from the industrial site. The direct danger to animal and vegetable life in such areas has been established. As a result, local ordinances and national regulations in the United States and various other countries have set increasingly strict limits on the permissible acid gas-content of effluent gases. A variety of methods have been proposed for dealing with this situation, but none has so far been wholly successful in dealing with the tri-partite problem of handling large volumes of hot effluent gas containing comparatively high concentrations of acid gases, reducing acid gas content to an acceptable level, and still maintaining an economical operation.